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Surface Effects on the Overall Young’s Modulus of FCC Metal Nanowires. Carmen M. Lilley, Mechanical Engineering. Surface effects, such as a surface elastic modulus and surface stress have been predicted for FCC NWs from atomistic simulations.
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Surface Effects on the Overall Young’s Modulus of FCC Metal Nanowires Carmen M. Lilley, Mechanical Engineering • Surface effects, such as a surface elastic modulus and surface stress have been predicted for FCC NWs from atomistic simulations. • Experimentally, elastic modulus measurements of FCC metal NWs have been found to vary widely. Some results indicate apparent size effects, other studies indicate no size effects. • For Nanoelectromechanical Systems (NEMS), accurate elastic properties are necessary to design devices. Modeling Surface Stress Effects on the Static Bending Behavior of Nanowires (NW). (a) Schematic of the undeformed and deformed NW centerline. (b) Cross-sectional view of a rectangular NW with the surface highlighted. (c) Cross-sectional view of circular NW with the surface highlighted.. • Model the elastic bending behavior of face centered cubic (FCC) metals with continuum mechanics. • Apply Young-Laplace Theory to study transverse load effects as a result of surface stress of nanowires (NWs) due to undercoordinated atoms at the surface. • Study the influence of boundary conditions on the resultant bending mechanical behavior of nanowires. • Test hypothesis that surface stress and boundary conditions affect the apparent elastic modulus of NWs. • Derived analytical solutions for NWs under static and dynamic bending. [1,2] • Validated theory that surface stress and boundary conditions affect the apparent elastic modulus measured experimentally. [1,2] • Proposed a surface effect factor as a qualitative parameter predict the influence of surface stress and geometry on the elastic behavior of static bending nanowires. [1,2] • Extending the method to large deformation of nanowires for application to NEMS resonators. [3] [1] J. He, C. M. Lilley, Nano Letters2008, 8, 1798. [2] J. He, C. M. Lilley, Applied Physics Letters2008, 93, 263108. [3] J. He, C. M. Lilley, Computational MechanicsIn Press.